Spray-dried porcine plasma affects intestinal morphology and immune cell subsets of weaned pigs

The aim of this study was to evaluate the effects of dietary spray-dried porcine plasma (SDPP) on the productive performance, intestinal morphology and leukocyte cell subsets of piglets. Sixteen early-weaned piglets (20 ± 2 d) were distributed into two dietary treatments: 1) free access to control diet or 2) 6% SDPP in the control diet instead of soy-protein concentrate. Intestinal morphometry of the small and large intestine, haematology and immune cell flow cytometric analysis of blood, ileo-colic lymph node and ileal Peyer's patches were performed in all pigs. Although SDPP treatment did not increase growth performance, it improved feed efficiency. We observed that SDPP diminishes blood monocytes, and macrophages (SWC3+), B lymphocytes (CD21+) and γδ T cells (γδTCR+) in gut lymphoid tissues. SDPP-treated piglets also showed lower intraepithelial lymphocyte numbers and lamina propria cell density in the small and large intestine. All these results suggest lower activation of the immune system of the SDPP-piglets during the post-weaning period. Moreover, the use of SDPP can be considered a valid alternative to antibiotic growth promoters.